In many clinical and hospital tests for the determination of duodenal or serum lipase activity, the lipase is admixed with a stabilized suspension of olive oil in an aqueous medium to present a triglyceride or triacylglycerol interface upon which the enzyme binds and accomplishes hydrolysis of the triglycerides. The efficiency of the lipase is then assessed by titration of the free fatty acid liberated during a specifc reaction period. Generally, a pH value of the aqueous dispersion is predetermined and when the pH is lowered to the predetermined value, a predetermined quantity of a dilute base is added to neutralize the fatty acids generated by the attack of the lipase on the triglyceride. A time versus volume of base plot provides a relative measure of the efficiency or activity of a given lipase. In assaying of this variety, particle size control is of great importance since the rate of reaction is dependent upon the surface area available to the lipase. If the triglyceride particles are relatively large, the hydrolysis rate will be relative low. Conversely, if the surface is relatively large, which is the case if the particles are very small, lipase hydrolysis rate will be relatively high. Thus, depending upon the stability of the triglyceride dispersions and their particle size, varying rates may be observed with no real difference in the activity of the lipase. Note Chemical Abstracts Volume 49; 12566d. The subject of hydrolysis at an oil/water interface is also discussed in Chemical Abstracts Volume 65; 2562g as well as Chemical Abstracts Volume 69; 41441n; Chemical Abstracts Volume 79; 144992t. Other attempts have been made to encapsulate enzymes such as that set forth in Chemical Abstracts Volume 73; 78221z and in Derwent Abstract 84877B/47.
Aqueous dispersions of triglycerides many times exhibit rather poor storage stability and exhibit a strong tendency to coalesce both in storage and during a test. Generally, such instability makes it difficult to determine the actual rate of lipolysis over any but the very early stages of hydrolysis of the triglycerides.
It would be desirable if there were available an improved method for the determination of lipase activity.
It would also be desirable if there were available an improved triglyceride dispersion which would provide a generally uniform surface area for a period of several hours.
It would also be desirable to have available an improved lipase activity test which would result in a more uniform evaluation of lipase activity.